The present application generally relates to an electrical power steering (EPS) system and particularly to EPS systems with two controllers and closed-loop control that includes integral action.
Typically, for reliability, an EPS system may use two independent controllers for calculating redundant motor control commands. Each command in turn drives a motor on a common shaft, such as a dual/wound motor. While the intent is for each of the two controllers to calculate the same control command, differences in sensor readings and latency between controller operating times lead to differences in calculated commands. Further when performing closed-loop control (such as controlling a measured motor position to a commanded motor position), the two controllers may end up with different values on integrator states, leading to large control commands, and thus, inefficiencies.